核磁共振测井.ppt

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1、1,核磁共振测井,2,Why NMR Logging,3,Why NMR Logging?,Porosity f,Saturation Sw,Permeability K,Sw 60%waterSw 40%oil40%Sw 60%oil+water,What will the reservoir produce?,Formation,4,Why NMR Logging?,Neutron/Density log responses,Porosity f,Solids,Complex mineralogy,Formation model,1.Less sensitivity to pore flu

2、ids than to solid matrix;2.Radioactivity sources.,5,Why NMR Logging?,Resistivity log responses,Water porosity fw,Formation model,Complex texture,1.No resolution to capillary bound water;2.Difficulty to determine clay bound water;3.No sensitive to hydrocarbon types,6,Why NMR Logging?,f Neutron,f Dens

3、ity,Resistivity Rt,Sensitive volumes are poorly definedBore hole fluids effectsMud cake effectsRugosity effectsDepth of investigation mismatchVertical resolution mismatch,7,Total Porosity Effective PorosityPore Size Distribution PermeabilityCBW/BVI/FFI,Hydrocarbon detection Hydrocarbon typing,Why NM

4、R Logging?,Log AnalystWhere are the HCs?How much HC?What type of HC?,PetrophysicistWhat are the fluids?What is the reservoir quality?What will flow?,Reservoir EngineerWhat will produce?At what rate?Which recovery strategy?,The NMR logging provides answers for:,8,NMR Physics,核磁共振是磁场中的原子核对电磁波的一种响应，原子核

5、由质子和中子组成，质子带正电，中子不带电。质子与中子统称为核子。所有含奇数核子以及含偶数个核子但原子序数为奇数的原子核，都具有内秉角动量（或叫“自旋”）。这样的核，自身不停地旋转，犹如一个旋转的陀螺。由于原子核带有电荷，它们的自旋将产生磁场，象一根磁棒，该磁场的强度和方向可以用核磁矩矢量来表示，即：=p 式中 磁矩；p自旋角动量；比例因子，被称做旋磁比，是磁性核的一个重要性质，每一个核都有一个特定的值，由实验测定。可以为正，亦可以为负，所以核磁矩的方向可能与核自旋角动量的方向相同或相反。当没有外加磁场时，单个核磁矩随机取向，因此，包含大量等同核的系统在宏观上没有磁性。,9,10,The Ori

6、gin of Magnetization,11,当核磁矩处于外加静磁场中时，它将受到一个力矩的作用，从而会象倾倒的陀螺绕重力场进行一样，绕外加磁场的方向进动，进动频率。又叫Larmor频率，是磁场强度与核旋磁比的乘积，即：o=Bo 式中，Bo为外加磁场的强度。由于不同的核值不一样，因此，在相同的外加磁场强度中，不同原子核的进动频率亦不相同。在外加磁场中，整个自旋系统被磁化，宏观上将产生一个净的磁矩矢量和。单位体积内，核磁矩的和，叫做宏观磁化量（M），即：M=i这个非零宏观磁化量与外加磁场Bo平行。,12,13,Nuclear Magnetism,+,+,+,+,+,+,+,Gyromagnet

7、ic Ratio():,Quantum Mech.View(Energy),Classical View(Orientation),high E,low E,DE,AppliedMagneticField,Bo,determines measurement frequencyh=Planks constantI=spin quantum number,单个自旋,自旋I=1/2的氢核,在外加磁场中,能级分裂成两个,即高能态和低能态,对应于核自旋进动的不同取向,14,对于被磁化后的自旋系统，再施加一个与静磁场垂直、以进动频率。振荡的交变磁场B1。从量子力学的角度说，此时交变场的能量等于质子两个能级

8、的能量差，会发生共振吸收现象，即处于低能态的核磁矩吸收交变电磁场提供的能量，跃迁到高能态，磁化强度相对于外磁场发生偏转，这种现象被称为核磁共振，交变电磁场既可以连续地施加，也可以以短脉冲的形式施加。现代核磁共振仪大多采用脉冲方法。它具有许多优越性，特别在提高信噪比方面。由于谱仪的工作频率大多在射频段，故把这样的脉冲电磁波叫做射频脉冲。,15,加上B1后与B0平行的磁化矢量M将被扳倒，磁化矢量被扳倒的角度与加给自旋的能量成正比，因此，取决于射频场的强度和长度（即连续施加的时间）.,16,M,M,M,q=90,f,90 pulse,180 pulse,90脉冲是指把磁化矢量扳转90的脉冲，从纵轴（

9、B0）方向扳转到水平面，并与B0及B1都垂直。180脉冲则引起磁化矢量的反转,17,测量方法,在核磁测井中测量核磁弛豫的方法主要有自由感应衰减、自旋回波、反转恢复法等。自由感应衰减法在井下测量简便易行，自旋回波法可以消除由于扩散而对测量结果带来的误差，便结果更为准确可靠，并且提高了信噪比。,18,19,0,t,2t,FID,Echo,90,180,Time(ms),Time(ms),1,2,3,4,5,自旋回波方法(90-180-),20,21,Time(ms),2t,4t,6t,8t,TE,90,180,180,180,180,22,弛 豫 在射频脉冲施加以前，自旋系统处于平衡状态，磁化矢量

10、与静磁场方向相同，射频脉冲作用期间，磁化矢量偏离静磁场方向，射频脉冲作用完后，磁化矢量又将通过自由进动，朝B0方向恢复，使核自旋从非平衡态分布恢复到平衡态分布。恢复到平衡的过程中叫做弛豫，它包含两种不同的机理：非平衡态磁化矢量的水平分量MX、Y衰减至零的过程称为横向弛豫过程，弛豫速率用1/T2来表示，T2叫做横向弛豫时间。横向弛豫过程中，自旋体系的内部相互作用，使磁化矢量进动相位从有序分布趋向无规分布。从此，自旋与晶格或环境之间不交换能量，自旋体系的总能量没有变化，所以，从微观机制上考虑，又把这个弛豫过程叫做自旋一自旋弛豫。,23,磁化矢量的纵向分量MZ恢复到初始磁化强度M0的过程，称为纵向弛

11、豫过程，弛豫速率用1/T1来表示，T1叫做纵向弛豫时间。在纵向弛豫过程中，磁能级上的粒子数要发生变化，自旋体系的能量也要发生变化，自旋与晶格或环境之间交换能量，把共振时吸收的能量释放出来，因此，在微观机制止，把它称做自旋一晶格弛豫。,24,0,2,4,6,8,10,12,14,0,M,0,Time(s),Exp(-t/T2),3,T2,decay 95%,18,16,Transverse Relaxation,25,26,M0,Polarization,NMR Signal Process,T1,T2,27,28,29,RF Pulse,Time,TE,90,180,180,180,180,S

12、 N,S N,Echo Signal,Time,TE,Antenna,Magnet mandrel,30,Time,Polarization T2 Polarization T2,T2 Decay,TE,TW,T1 Buildup,M0.e-t/T2,M0(1-e-t/T1),31,Tw,Te,Tw=wait time Te=interecho timeNe=Number of echoesRA=running average,time,time,Data Acquisition,32,From a Echo Train to a T2 Distribution,33,物质的弛豫特征 存在三种

13、影响T1或T2弛豫时间的NMR弛豫机理：即颗粒表面弛豫、梯度场中分子扩散引起的弛豫和体积流体进动引起的弛豫 表面弛豫:流体分子在孔隙空间内不停地运动和扩散，在NMR测量期间扩散使分子有充分机会与颗料表面碰撞。在大部分岩石中，颗粒表面弛豫对T1和T2的影响最大。体积弛豫:岩石孔隙中的流体固有的弛豫。,扩散弛豫:在梯度场中分子扩散造成的弛豫为扩散弛豫。,34,Physics of NMR Logging Tool,35,当前，世界上能够提供核磁共振测井服务的主要有3家，即俄罗斯、斯仑贝谢和Numar。当代核磁共振测井可分为三种类型：（1）大地磁场型：以俄罗斯生产和制造为主，目前已广泛用于俄罗斯、鞑

14、靼、秋明、哈萨克斯坦等地区，年测井近1000口井。（2）脉冲强磁场贴井壁型：斯化贝谢公司研制并投入生产使用。（3）成象测井型：美国Numar公司研制并投入生产使用。大庆测井公司2000年7月引进了美国哈里伯顿能源服务公司的MRIL-P型核磁共振测井仪，它是C型仪器的扩展和完善。,36,MRIL in Wellbore,MRIL Probe,Borehole,SensitiveVolumeCylinders(each 1 mm thickat 1 mm spacing),24“,16”,37,f1,f2,Using Multiple Frequencies,f3,Improves Logging

15、 Speed Increases Signal to Noise,38,仪器的探头由一个永久磁铁，一个射频脉冲（RF）发射器及一个射频接受器。仪器具有以下特点：(1)24英寸的永久磁铁在井眼周围地层产生梯度静磁场。（2）仪器居中测量，在探测体积范围内，消除了井眼泥浆信号，可获得较高的测量信噪比。（3）P型核磁测井仪器具有9个观测频率，它测量的信息，是地层中9个厚度约1mm的壳体内流体的贡献。大大方便了各种不同观测模式的设计和实现，并提高了测井作业的效率。（4）MRILP型仪器一次下井可进行标准T2测量，双等待时间测井和双回波间隔测量。保证了测量的稳定性，大大提高了井场的工作效率。（5）MRIL

16、P型仪器的最小回波间隔可达到0.6ms，实现了对粘土水信号的观测，因此可获得地层的总孔隙度和粘土束缚水体积。,39,MRIL-Prime Shells,16”250F,MRIL Prime Probe,Borehole,9 SensitiveVolumeCylinders(each 1 mm thickat 1 mm spacing),24”,1”,760kHz,580kHz,40,Tw=12s,Single Frequency ToolMRIL-B,CMR 3 ft/min.,92%idle,Dual Frequency ToolMRIL-C6 ft/min.,85%idle,Nine Fr

17、equency Tool(8 freq.shown)MRIL-Prime Tool24 ft/min.,TE=3.6ms,TW=8s,Total porosity with Dual TE and Dual TW in a single pass to cover all types of formation fluids that might be encounter in an exploration/development well.,41,0,1000,0,30,30,time msec,30,single volume,dual volume,8-volume,MRIL-Prime

18、Data Quality,-improved data quality with the MRIL-Prime tool,42,43,44,45,46,47,MRILP型仪器的测量方式 MRILP型核磁共振测井仪有四种基本的观测模式：（1）单Tw/单TE模式，用DTPTW或D9TPTW表示。由于测量泥质束缚水、毛管束缚水、视总孔隙度、视有效孔隙度、渗透率，不能做流体类型识别。（2）双TW/单TE模式，用DTW或D9TW表示，该模式是一种T1加权观测，除了用于测量泥质束缚水、毛管束缚水、视总孔隙度、视有效孔隙度外，还可以单独用作油气识别，并且，通过非完全磁化和含氢指数校正，获得地层的真有效孔隙度

19、和真总孔隙度。（3）单TW/双DTE模式，用DTE（n）TW 和 D9TE（n）TW表示，该模式是一种扩散系数加权观测，可以测量泥质束缚水、毛管束缚水、视总孔隙度、视有效孔隙度，也可以对粘度较高的油进行识别和定量分析。双Tw/双TE模式，用DTWE（n）或D9TWE（n），该模式既利用了扩散系数加权又利用了T1权观测，可以测量泥质束缚水、毛管束缚水、视总孔隙度、视有效孔隙度、以及对轻烃、高粘度油的识别和定量分析，是一类对新区有效的观测模式。,48,MRIL-P型仪器的特点,1、孔隙度重复性为1个标准偏差。2、垂向分辨率：标准模式为6 feet。高分辨率模式4 feet。静止分辨率为2 feet

20、。3、泥浆电阻率最低为 0.02 欧姆.米。4、最高工作温度175。5、最大工作压力20000 psi。6、井眼条件：7、仅适用与裸眼井。,49,MRILP型核磁共振测井测前设计 为采集高精度的测井资料，采集到我们所需要的测井信息必须做好测前设计，做好测井设计的关键是要准确地确定储层流体的核磁特性，（T1、T2）而识别流体、核磁持性的几个关键参数有地层温度、地层压力、地层水矿化度、泥浆类型、油气比重、地层温度下的油气粘度等。在了解上述信息后，要做好测井方式，参数选择等准备工作。,50,MRILProcessing&Interpretation,MRIL Corrections&Quality

21、Control:,Quality Control Curves:,B1MOD+/-5%of B1 CalibrationCHI 2(Curve to fit quality)GAINPHNO 1.0(Standard Deviation of channel after rotation)PHER 0.0(Mean of the noise channel)PHAN 60 or 240 deg.(Phase Angle),MRILCorrections,51,测井后的质量检查主要从以下几个方面进行测井资料质量检查各种观测模式测井有效孔隙度（MPHI）总孔隙度（MSIG）。双TW测井中的MPHI

22、TWSMPHITWL 双TE测井中的MPHITELMPHITES核磁有效孔隙度与中子密度交会孔隙度的一致性，要求在水层处MPHIXPHI;在纯气层处经轻烃校正后MPHI中子孔隙度;在砂岩处MPHI密度孔隙度。,52,NMR Applications in Petrophysics,53,核磁共振测井解释原理,Echo,Amplitude,0,15,150,135,120,105,90,75,60,45,30,Time(ms),20,15,10,5,0.00,1.00,2.00,3.00,4.00,0.1,1,10,100,1000,10000,MBVI,MBVM,4.00,0.00,1.00,

23、2.00,3.00,Incremental Porosity(,pu,),MCBW,Clay-,Clay-,Bound,Bound,Water,Water,T2 Decay,MRIL Porosity,T2 Decay(ms),T2 Cutoffs,54,T2,T2,T2,T2,T2,time,time,time,time,time,Pore Size and T2(Water),55,Fluid on the surface has rapid relaxation rate,1H,Bulk fluids have lower relaxation rates,Basic relaxatio

24、n mechanisms for fluids in rock pores:Bulk relaxation for both T2 and T1Surface relaxation for both T2 and T1Diffusion relaxation for T2,Diffusion,56,NMR-Pore Size(Sandstones),f=17.1%Kair=1.87 mdSwir=80.8%f=24.4%Kair=45.1mdSwir=58.3%f=11.8%Kair=414 mdSwir=29.6%f=27.8%Kair=2640 mdSwir=21.3%,.001.01 0

25、.1 1.0 10 100,Radius,microns,Radius(HgI)T2(NMR),57,核磁共振测井的测井方式及处理解释方法核磁共振测井的地质应用,58,Dual TE,Effective Porosity,Activation selection,Objectives to run MRIL,Dual TW,Total Porosity,59,双等待时间测井方式,适用于:轻质油(viscosity up to 5 cp)识别天然气,60,61,Direct Hydrocarbon TypingDifferential Spectrum Method,NUMAR Corp.,19

26、95,1 10 100 1,000 10,000,T2 Time(ms),BrineGasOil,Long RecoveryTime(TR),Short RecoveryTime(TR),Difference,62,0,M0,Time(s),T1 relaxation contrast mechanism,Water,Hydrocarbon,TWshort,TWlong,1 10 100 1000 T2(ms),TWshort,1 10 100 1000 T2(ms),TWlong,Polarization and echo acquisition,T2 distribution,63,64,

27、Matrix&Dry Clay,ClayBoundWater,CapillaryBoundWater,MoveableWater,Light Oil,ClayBoundWater,CapillaryBoundWater,MoveableWater,Light Oil,Oil base mud filtrate,Porosity,Porosity,1101001,000,T2(ms),Long TW,Short TW,Oil-base mud,ClayBoundWater,CapillaryBoundWater,MoveableWater,Light Oil,Water base mud fil

28、trate,Porosity,Porosity,1101001,000,T2(ms),Long TW,Short TW,Water-base mud,65,Matrix&Dry Clay,ClayBoundWater,CapillaryBoundWater,MoveableWater,Gas,ClayBoundWater,CapillaryBoundWater,MoveableWater,Gas,Oil base mud filtrate,Oil-base mud,Porosity,Porosity,1101001,000,T2(ms),Long TW,Short TW,ClayBoundWa

29、ter,CapillaryBoundWater,MoveableWater,Gas,Water base mud filtrate,Water-base mud,Porosity,Porosity,1101001,000,T2(ms),Long TW,Short TW,Oil base mud filtrate,Formation gas,66,Matrix&Dry Clay,ClayBoundWater,CapillaryBoundWater,MoveableWater,Light Oil,Gas,ClayBoundWater,CapillaryBoundWater,MoveableWate

30、r,LightOil,Gas,Water baseMud filtrate,ClayBoundWater,CapillaryBoundWater,MoveableWater,LightOil,Gas,Oil baseMud filtrate,1 10 100 1,000,T2(ms),Porosity,Porosity,Long TW,Short TW,Water-base mud,1 10 100 1,000,T2(ms),Porosity,Porosity,Long TW,Short TW,Oil-base mud,67,68,t,Raw Data:Echo Train A(long TW

31、),M(t),t,Raw Data:Echo Train B(short TW),M(t),Data Process for Results in Echo Time Domain,69,MRILProcessing&Interpretation,Matrix&Dry Clay,ClayBoundWater,Capillary BoundWater,MoveableFreeWater,Oil,Gas,Conductive Fluids,MPHI,MCBW,MFFI,PHIT,MRIL,MBVI,MRIL Porosity for two fluid phase,fMRIL=f.Sxo+f*(1

32、-Sxo).Hl*.(1 etw/T1),water,HC,fMRIL=f.Hl.(1 etw/T1),70,MRILProcessing&Interpretation,TDA_COMP,The Porosity Measured by MRIL is Subject to Hydrogrn Index HIand Polarization T1 effects.,fTw=f.HI.(1-e-Tw/T1),f.HI.(1-e-TwL/T1),f:True Hydrocarbon PorosityfTw:Measured Hydroc.Porositytw:Wait TimeHI:Hydroge

33、n IndexfTwLu:Porosity from TwL of uniqueFluid phasefTwSu:Porosity from TwS of uniqueFluid phaseTwL:Long Wait TimeTwS:Short Wait Time,T1 estimation is based onthe Ratio r=fTwLu/fTwSu,r=,f.HI.(1-e-TwS/T1),1-e-TwL/T1,=,1-e-TwS/T1,71,MRILProcessing&Interpretation,TDA_COMP,fgas is calculated by correctin

34、g for HIgas&T1gas,fg:Gas Porosityfg*:Apparent Gas Porosity seen by echo differenceHIg:Hydrogen Index of Gasfo:Oil Porosityfo*:Apparent Oil Porosityseen by the echo differenceHIo:Hydrogen Index of OilT1h:T1 of either Gas or Oil,foil is calculated by correcting for HIoil&T1oil,72,MRILProcessing&Interp

35、retation,TDA_COMP,Corrected Porosity for T1 and HI,Fully Polarized Liquid Porosity from Long Tw,PhiFPL=MPHIA-,fg.HIg.(1-e-TwL/T1g)+fo.HIo.(1-e-TwL/T1o)+f w.HIw.(1-e-TwL/T1w),TDAMPhi=PhiFPL+fg+fo+fw,73,MRILProcessing&Interpretation T.D.A.MRIL Time Domain Analysis,Matrix&Dry Clay,ClayBoundWater,Capill

36、ary BoundWater,MoveableFreeWater,Oil,Gas,Conductive Fluids,MPHI,MCBW,MFFI,PHIT,MRIL only,MBVI,MRIL+MRIAN,EPOR,CBVWE,TPOR,MRIL+MRIANTDA_COMP,74,Time Domain Analysis1.直接判断烃的类型2.直接求有效孔隙度3.不依靠电阻率直接求取 Sxo.,75,适用于:重油(up to 50 cp)确定Sw,Sor确定 Fw(free water),双TE测井方式,76,SSM for case 1.,77,SSM for case 1.,78,79

37、,Based on the thermal diffusion properties of fluids in the pore space,D:Diffusivity of Fm.FluidDW:Diffusivity of Waterat Fm.Temp.&Press.=2.5 cm2/sec.at 23 C&1 atm press.,MRI Log-DiffustionProcessing&Interpretation(DIFAN),80,Concept T2 and D,81,Concept T2 and D,surface relaxationbulk fluid relaxatio

38、n,T2 is a function of surface and bulk fluid relaxation,Thus in a dual TE experiment the computedD=Doil+DwaterThe RatioD/DwFor a T and P,the DW can be calculated byDw=12.5(T(K)1/2*exp-0.000522*P(bar)+925*exp-(0.00026*P(bar)/(T(k)-95-0.0261*P(bar)Given as RDDWprovides a contrast to Determine Saturati

39、on,In water wet Rocks:,82,83,MRILProcessing&Interpretation,Matrix&Dry Clay,ClayBoundWater,Capillary BoundWater,MoveableFreeWater,Oil,Gas,Conductive Fluids,MPHI,MCBW,MFFI,PHIT,MRIL,MBVI,MRIL Permeability,84,85,86,核磁与常规测井方法组合的测井解释方法,1.NMR and Resistivity Logging(MRIAN)2.NMR and Density LoggingFor true

40、 porosity,and gas-saturation in flushed-zone.(DMR),87,MRIL and the C.C.D.dual water model,88,WELL:C/tp Clay,ZONE:15500.000-16100.000 FT,MRIL Swb,0,1,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,CWA w/MPhiT,0,50,5,10,15,20,25,30,35,40,45,GAMMARAY,10,110,26.6667,43.3333,60,76.6667,93.3333,Swt=100%,Swt=Swb,Depe

41、nds on W,Cwa=1/(Rt*(water),Swb,Ccw,Cwa=Cw+Swb(Ccw-Cw),Cwa=(Swb)wCcw,89,When Swt100%and Swb=0.0,Determining,90,When Swt=100%,&Swb0,91,Selecting w in MRIAN,Wet zone,Irreduciable water zone,92,PHIT,Invaded zoneOil base mud,Virgin zone,93,ECHOSTRIP,PROCESS_T2d,T2_TOOLKIT,PRE_MRIAN,SWB_MRIAN,MRIAN,m.cls,

42、m.cls,d.cls,d.cls,d.cls,d.cls,FINAL PRODUCTMRIAN,校深,94,95,ECHO_STRIP 需要 m.cls文件 需要“dpp_act_db.txt”文件(改activation 及 Running average)仅处理3组文件 进行Running average 和相位校正后将Echo trains to Porosity bins 输出的“EDIF”应用在T.D.A中,96,PROCESS_T2d将时间域(m.cls)文件转换成深度域(d.cls)的文件需要一个配置文件config_1_grp_ft.m.2dconfig_1_grp_m.m.2dconfig_2_grp_ft.m.2dconfig_2_grp_m.m.2dconfig_3_grp_ft.m.2dconfig_3_grp_m.m.2d自然伽玛曲线没有刻度,PR06,grpA+PR06,grpA+grpBPR06,97,T2_TOOLKIT 用d.cls文件 计算MBVI、MPHI、MSIG、K 输出所有组的 T2_谱 计算理论上的烃的特性 对所有孔隙度(bin)进行平滑滤波 输出T.D.A的结果,98,为MRIAN准备数据,